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[An additively decomposable inequality measure is one which can be expressed as aweighted sum of the inequality values calculated for population subgroups plus the contribution arising from differences between subgroup means. The paper derives the entire class of measures which are additively decomposable under relatively weak restrictions on the form of the index. The subclass of mean indepedent measures turns out to be a single parameter family which includes thesquare of the coefficient of variation and two entropy formulae proposed by Theil.]

[The paper explores some of the issues involved in constructing measures of mobility when the data are provided in the form of a transition matrix. An initial set of axioms is proposed which is inconsistent. They can, however, be reconciled if empirically unlikely transition matrices are eliminated from consideration. The paper then discusses the problem of comparing matrices not defined over the same interval. An index based on the convergence speed in a Markvov chain process is able to compensate for differing time periods.]